There are handling issues based on exactly where on the axle a single upper arm is placed, having to do with overall power, link angles, etc. However, none of us understand it, and for what we do it really doesn't matter. The only person I've talked to who understands that is Drew Burroughs from Poly Performance (goat1 on Pirate). My upper arm is on the passenger side. Quite a few of the guys that I wheel with regularly have 3 links, and some are on the pass side and some on the drivers side.
I made mine on the pass side because of ease of fabricating (room), and because I liked the idea of the upper arm and the track bar being mounted together.......sort of makes a long A arm out of those two links. My track bar is mounted very high on the axle, which raises the roll center and aids stability, and the mount for the upper arm and track bar is very stout. I did have trouble twisting the axle tube on the passenger side once, but I partially contribute that to the fact that my D44 axle housing was bent when I got it and I had to have it straightened, which I think weakend the press in fit. To be safe, on any pass side 3 link that's not on a 9" housing, I'd put a bead on the tube to center section joint. It's very likely not an issue on a D60.
A track bar is your friend, I don't at all get folks who look for ways to eliminate a track bar like it is some kind of necessary evil. Especially on the front of an XJ, where room is tight because the engine is placed so far forward, a 3 link is a very good idea. With a 3 link there is more room to raise the upper arm to get better link geometry, and the track bar placement determines the roll center. On a triangulated 3 or 4 link it is harder to get the link placement right to give good geometry because the engine is in the way. I believe that the proper link geometry, the length and angles of the control arms and the placement of the track bar, is much more important than which side the upper arm is placed. Like I've said in all of the recent threads on 3 links, just be sure that all of the mounts are stout, since you don't want a link or mount breaking on a 3 link.